PARENT SESSION
PS9 - Plant Toxicology
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P109) Adverse Effects of Pavement Anti-icers and Deicers to Ponderosa Pine.

Pillard, David^*,1, Gensemer, Robert¹, ¹ ENSR International, Ft. Collins, CO, USA

ABSTRACT- Road salts are commonly used as anti-icers and deicers throughout the United States. At the U.S. Air Force Academy in Colorado Springs, Colorado, salts are used to keep Academy roads snow- and ice-free. Adverse health of roadside stands of ponderosa pine (Pinus ponderosa) was believed to be associated with application of salts including MgCl₂ and NaCl. Soil and plant (needle) tissue samples were collected in the spring (following winter deicing) and fall (just prior to the deicing season). Samples were analyzed for ions associated with anti-icer/deicer salts (Cl^-, Mg²⁺, Na⁺) and major nutrients. Laboratory studies with lettuce and ryegrass were used to quantify the toxicity of soil samples as well as several commercial deicers. Both Cl^- and Mg²⁺ were significantly elevated in plants exposed to deicer applications. Field data suggested that adverse effects were more closely associated with NaCl than MgCl₂. Laboratory germination studies supported these results in that seedling germination was strongly inhibited in soils with the highest Cl^- and Na⁺ concentrations. Furthermore, root and shoot growth were directly correlated with sodium and chloride rather than magnesium.

Key words: deicers, salt, anti-icers, pine trees